8.3. Highlights of 1394b

1394b [2] is capable of higher throughputs over longer connection lengths. They are made possible by using a new overlapped and pipelined arbitration mechanism. This mechanism is built up on a two-pair full-duplex transmission method with coded control and request symbols as well as 8B10B encoded packets. It enables the easy adaptation of different transmission media by the same transceiver architecture.

8.3.1. Summary of New Capabilities

New specifications of 1394b make FireWire connections run faster and go further. Higher throughputs of 800 Mbps (S800) and 1600 Mbps (S1600) have been defined. Longer reaches of 50 and 100 m have been made possible on Category 5 unshielded twisted pair and plastic/glass optical fiber. Thicker shielded twisted pair cables of 2 and 4.5 m have been introduced to accommodate these higher throughputs along with some new plugs. Category 5 unshielded twisted pair (UTP5) can carry a throughput of 100 Mbps over a distance of 100 m based on the 100BaseTX PHY technology defined by the ANSI X3.263-1995 standards [3]; plastic optical fiber (POF) can provide a throughput of 200 Mbps at a distance of 50 m; hard polymer clad fiber (HPCF) is able to reach 100 m at 200 Mbps; and glass multimode fiber (MMF) will run up to 1600 Mbps at 100 m as summarized in Table 8.1. The vertical cavity surface emitting laser, VCSEL, is used in conjunction with MMF.